In packages with dangerous contents, especially pharmaceutical preparation packages, it is desirable to prevent small children who happen to have gained access to the package gaining access to its contents. In the packaging field, various solutions have been proposed for solving this problem.
EP 1 002 744 A1 describes a cardboard package with a locking system for children, with an outer casing and an inner sliding part. The sliding part is prevented from being drawn out of the casing unless a locking system has been inactivated by pressing on a release button. The locking system functions by virtue of a tab on the sliding part coming into contact with a shoulder on the inside of the casing. The shoulder is formed by virtue of an inner cardboard ply, glued to an outer ply, being provided with a cutout. A disadvantage of this construction is that, for the locking system to function, it relies on the shoulder having sufficient height by virtue of the thickness of the inner cardboard ply. The locking function is thus made dependent on the selection of a sufficiently thick material for the casing. A material which is too thin can result in the locking security being put at risk. Moreover, it is likely that the construction will lead to the shoulder being worn down on repeated use, and that its function will be impaired after a number of openings of the package.
Patent document PCT/SE01/02496 describes a package with a locking arrangement for preventing small children opening the package and gaining access to its contents. The package comprises a sleeve into which an insert part can be inserted. The insert part is provided with a locking tab which, by contact with a stop tab designed on the inside of the sleeve; prevents the insert part being drawn out of the sleeve. In order to cause the stop tab to be located in the way of the locking tab in the drawing-out direction of the insert part, the stop tab is provided with a projecting part which, by bearing against one of the walls of the sleeve, causes the stop tab to be located at an angle to the wall so that it projects into the path of the locking tab. To draw out the insert, it is necessary for the user to manoeuvre the locking tab so that it is moved so that it is located outside the area of the stop tab in the drawing-out direction.
A problem with the solution in PCT/SE01/02496 is that the projecting part on the stop tab involves difficulties in the manufacture of the package. In the usual case of the sleeve being manufactured from a cardboard blank, the projecting part is produced by the blank being punched and stamped, a bowl-shaped portion being formed in the blank. This must take place before the sleeve is glued together. During gluing, the glued surfaces are pressed against one another in an automated process. In this regard, special consideration has to be given to the projecting part produced by punching, so that the latter is not flattened out. Both the stop tab and the glued surfaces are produced at the edge of the cardboard blank, which means that the stop tab is located in direct proximity to the glued surfaces. In this regard, the pressing-together stage in the gluing process is made even more difficult.
The package in PCT/SE01/02496 comprises a locking tab which is produced by folding the insert blank. In the inserted position of the insert part in the sleeve, the locking tab extends inside the package, essentially from the lower wall to the upper wall thereof. The locking tab is manoeuvred by means of a manoeuvring tab on the top side of the package, where the locking tab has a free end.
A problem of this solution is that, in the event that the package is designed so that it is relatively tall, that is to say the distance between the lower wall and the upper wall is great, the locking tab is long. It then has inferior strength because it has a great buckling length. There is then a great risk that, instead of being folded in the intended manner when manoeuvring takes place, the locking tab will be deformed by buckling. Another problem is that the locking tab is relatively bulky, which makes it necessary for the package to be made larger than its contents require.
A further problem with the design of the locking tab according to PCT/SE01/02496 is the following. The locking tab is arranged so as to extend from the bottom of the package through the same at an angle to its walls. The angle is required because manoeuvring of the locking tab takes place from the top side of the package and, when the locking tab is manoeuvred, it is pivoted about its attachment to the insert part so that the angle is changed. In the event that the package is designed so that it is relatively tall, the angle of the locking tab makes it necessary for the package to be sufficiently wide as well. This imposes limits on the design possibilities for the package. The problem is even more apparent in the event that two locking tabs are used in the manner proposed in PCT/SE01/02496. The locking tabs are then located side by side in the transverse direction of the package, and, when a tall package is to be produced, a great width is required in order to accommodate the two long angled locking tabs and afford them sufficient movement space.